The Wolf Pack has been around for some time, mine is easily over 20 years old, yet they just keep on going. Occasionally after lending them out, I have to replace a clip ( available at good outdoor shops), despite warning that one must open all 4 clips before lifting the lid off. I have never ever measured the exact size but my high-top versions are around 35 + litres with the low top versions being around 31 litres. Big enough for a variety of options without breaking ones back. Mine have seen duty carrying books and magazines for a trip, toys, groceries and even all the plates and utensils one needs for an extended trip away.
You can even use them to pack clothes – simply put the clothing in large zip-lock bags, expel the air and you have a wardrobe. Thanks to the grooved lids and base they stack atop each other and do not slide around if properly secured when off-road.
They are tough being made from HDPE, yet are useful around camp, stand on them to load things, sit on them or even use them as a low table to serve drinks or prep food (with a suitable board otherwise things could fall).
They pack nicely on roof racks, some even having retention devices to keep them in place. They will not survive a storm so I keep mine in a bag and have closed the tiny holes in the base with duct tape, to stop dust and water getting in.
The various fitment centres stock a variety of accessories and even padded inserts for storing sensitive items. I just love the design, functionality and durability. In fact, I always keep one packed with important bits and pieces for a trip as well as using one as my bush kitchen.